> For the complete documentation index, see [llms.txt](https://docs.arkelectron.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arkelectron.com/products/sensor/ark-mag/firmware.md).

# Firmware

ARK MAG runs the [PX4 DroneCAN Firmware](https://docs.px4.io/main/en/dronecan/px4_cannode_fw.html). As such, it supports firmware update over the CAN bus and [dynamic node allocation](https://docs.px4.io/main/en/dronecan/#node-id-allocation).

The flight controller flashes the node firmware over CAN.

{% embed url="<https://docs.px4.io/main/en/dronecan/#firmware-update>" %}

* Firmware target: `ark_mag_default`
* Bootloader target: `ark_mag_canbootloader`

Node firmware built in October 2026 or later can rewrite its own CAN bootloader: set `SYS_BL_UPDATE` to `1` on the node. The flight controller logs `bootloader updated`, `bootloader unchanged` or `bootloader update failed`, and the parameter returns to `0`.

## Node Parameters

Set these on the ARK MAG, then reboot it. Use [QGroundControl](https://docs.px4.io/main/en/dronecan/#qgc-cannode-parameter-configuration), where each CAN node is a separate *Component X* under **Vehicle Settings > Parameters**, or the [DroneCAN GUI Tool](/knowledge-base/knowledge-base/dronecan-gui-tool-guide.md).

| Parameter         | Default | Description                                                                                                                 |
| ----------------- | ------- | --------------------------------------------------------------------------------------------------------------------------- |
| `CANNODE_TERM`    | 0       | Set to `1` on the last node of the CAN bus                                                                                  |
| `CANNODE_NODE_ID` | 0       | Fixed node ID (1–125). `0` uses dynamic node allocation                                                                     |
| `CANNODE_PUB_MAG` | 1       | Publish magnetometer messages on the CAN bus                                                                                |
| `SYS_BL_UPDATE`   | 0       | Set to `1` to rewrite the CAN bootloader from the running firmware. Firmware built before October 2026 lacks this parameter |


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